IOT/MainModule/ViewModels/MainViewModel.cs

using Model.Entity;
using Prism.Commands;
using Prism.Ioc;
using Service.Interface;
using System.Collections.ObjectModel;
using System.Windows.Input;
using UIShare.ViewModelBase;

namespace MainModule.ViewModels
{
    public class MainViewModel : NavigateViewModelBase
    {
        #region 属性
        
        private ObservableCollection<PostEntity> _posts;
        public ObservableCollection<PostEntity> Posts
        {
            get => _posts;
            set => SetProperty(ref _posts, value);
        }

        private string _searchKeyword;
        public string SearchKeyword
        {
            get => _searchKeyword;
            set => SetProperty(ref _searchKeyword, value);
        }
        
        #endregion
        
        #region 命令
        
        public ICommand CreatePostCommand { get; set; }
        public ICommand SearchCommand { get; set; }
        public ICommand CategorySelectCommand { get; set; }

        #endregion
        #region 私有字段
        private IContainerProvider _containerProvider;
        private IPostService _postService;
        private IDialogService _dialogService;
        #endregion
        public MainViewModel(IContainerProvider containerProvider ) : base(containerProvider)
        {
            _containerProvider=containerProvider;
            _postService = containerProvider.Resolve<IPostService>();
            _dialogService = containerProvider.Resolve<IDialogService>();
            InitializeCommands();
            LoadPosts();
        }

        private void InitializeCommands()
        {
            CreatePostCommand = new DelegateCommand(OnCreatePost);
            SearchCommand = new AsyncDelegateCommand(OnSearch);
            CategorySelectCommand = new AsyncDelegateCommand<string>(OnCategorySelect);
        }

        #region 命令处理

        private async void OnCreatePost()
        {
            // 这里可以导航到发帖页面
            ShowInfoMessageBox("跳转到发帖页面",null);
        }

        private async Task OnSearch()
        {
            // 执行搜索逻辑
            if (!string.IsNullOrWhiteSpace(SearchKeyword))
            {
                await SearchPostsAsync(SearchKeyword);
            }
        }

        private async Task OnCategorySelect(string category)
        {
            // 按分类筛选帖子
            await FilterPostsByCategoryAsync(category);
        }

        #endregion

        #region 业务方法

        private async Task LoadPosts()
        {
            try
            {
                var result = await _postService.GetRecommendedPostsAsync(20);
                if (result.IsSuccess)
                {
                    Posts = new ObservableCollection<PostEntity>(result.Data);
                }
                else
                {
                    ShowErrorMessageBox("帖子加载错误",null);
                }
            }
            catch (Exception ex)
            {
                ShowErrorMessageBox($"加载帖子异常: {ex.Message}", null);
            }
        }

        private async Task SearchPostsAsync(string keyword)
        {
            try
            {
                var result = await _postService.SearchPostsAsync(keyword);
                if (result.IsSuccess)
                {
                    Posts = new ObservableCollection<PostEntity>(result.Data);
                }
                else
                {
                    ShowErrorMessageBox("查询帖子失败", null);
                }
            }
            catch (Exception ex)
            {
                // 处理异常
                ShowErrorMessageBox($"查询帖子异常: {ex.Message}", null);
            }
        }

        private async Task FilterPostsByCategoryAsync(string category)
        {
            if (category == "全部")
            {
                await LoadPosts(); // 重新加载所有帖子
                return;
            }
            
            try
            {
                var result = await _postService.GetPostsByCategoryAsync(category, 20);
                if (result.IsSuccess)
                {
                    Posts = new ObservableCollection<PostEntity>(result.Data);
                }
                else
                {
                    ShowErrorMessageBox("加载分类子失败", null);
                }
            }
            catch (Exception ex)
            {
                ShowErrorMessageBox($"获取分类帖子异常: {ex.Message}", null);
            }
        }

        #endregion
    }
}